Does anyone know of any resources (classes or otherwise) that could be used to solve linear programming models using PHP? This is similar to Solver in Excel.

Basically, I have a model where the user inputs their preferences and it generates a solution given certain constraints. There is the potential for just building this from scratch but I would like to avoid that if possible just because of the complexity of the whole thing and the existence of solvers (granted, I've only found ones for Excel).

I saw something on SourceForge about lpsolve(). Has anyone had any experience with this?